SRAM and Shimano

[Danny521]

Hi I’ve got 2 bikes one with sram wireless shifter and one with cable shimano gears both bikes are 12 speed I’m wondering with out getting my self new wheels as one is 27.5 and one is 29 so can’t swap over would the seam wireless shifter work on the shimano cassette and shimano chain and then the other way round would shimano gears work on a sram cassette and sram chain as they both 12 speed sorry if it sounds dum just looking for advice before I mess around just wonder if anyone as done the same thank you

 

[nickf]

It's not a dumb question. In mechanical systems the indexing (ie by how much the cable is pulled) is done at the shifter. The derailleur design then has a "leverage ratio" which determines by how much the derailleur arm will move laterally for a given cable pull. The amount of lateral movement needs to correspond precisely to the lateral spacing between the rings on the cassette, Naturally Shimano and Sram choose to use different ratios at both the shifter and derailleur! So you can't just mix and match between shifters and derailleurs from the two brands.

However, what's key here is that (whatever the brand of shifter/derailleur) the derailleur arm moves laterally just the right amount for the cassette. You could try putting the 27.5 wheel on the 29er bike and seeing if the derailleur movement works across the whole cassette. If so, then it should also be OK with the other configuration. However, you will probably need to reset the end stops of the derailleur to match the cassette when you swap.

I don't have experience with electronic shifters, so others here might be able to confirm or refute what I've just said, but the principles are the same.

 

[Danny521]

It's not a dumb question. In mechanical systems the indexing (ie by how much the cable is pulled) is done at the shifter. The derailleur design then has a "leverage ratio" which determines by how much the derailleur arm will move laterally for a given cable pull. The amount of lateral movement needs to correspond precisely to the lateral spacing between the rings on the cassette, Naturally Shimano and Sram choose to use different ratios at both the shifter and derailleur! So you can't just mix and match between shifters and derailleurs from the two brands.

However, what's key here is that (whatever the brand of shifter/derailleur) the derailleur arm moves laterally just the right amount for the cassette. You could try putting the 27.5 wheel on the 29er bike and seeing if the derailleur movement works across the whole cassette. If so, then it should also be OK with the other configuration. However, you will probably need to reset the end stops of the derailleur to match the cassette when you swap.

I don't have experience with electronic shifters, so others here might be able to confirm or refute what I've just said, but the principles are the same.

I’m not sure if the 27.5 fits on the 29 one but I’ll take a look at that I suppose if it does that’s one way to tell the the sram wireless shifter will work on the shimano cassette

 

[nickf]

I’m not sure if the 27.5 fits on the 29 one but I’ll take a look at that

Why wouldn't it fit?

 

[Danny521]

Why wouldn't it fit?

Because it’s not made for 27.5 but then again even if it not (I know some have a flip so u can put a 27.5 on rear) it’s not like I’m fully riding it I’m just checking if the sram wireless shifter will work on the shimano cassette